title: Convergent evolution of floral signals underlies the success of Neotropical orchids.
abstract: The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry--a form of Batesian mimicry that involves multiple models and is more complex than a simple one model-one mimic system--operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant-animal interactions.
authors.affiliation: Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK.
authors.forename: Alexander S T
authors.initials: AS
authors.lastname: Papadopulos
authors.forename: Martyn P
authors.initials: MP
authors.lastname: Powell
authors.forename: Franco
authors.initials: F
authors.lastname: Pupulin
authors.forename: Jorge
authors.initials: J
authors.lastname: Warner
authors.forename: Julie A
authors.initials: JA
authors.lastname: Hawkins
authors.forename: Nicolas
authors.initials: N
authors.lastname: Salamin
authors.forename: Lars
authors.initials: L
authors.lastname: Chittka
authors.forename: Norris H
authors.initials: NH
authors.lastname: Williams
authors.forename: W Mark
authors.initials: WM
authors.lastname: Whitten
authors.forename: Deniz
authors.initials: D
authors.lastname: Loader
authors.forename: Luis M
authors.initials: LM
authors.lastname: Valente
authors.forename: Mark W
authors.initials: MW
authors.lastname: Chase
authors.forename: Vincent
authors.initials: V
authors.lastname: Savolainen
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology; D005075:Biological Evolution; D003116:Color; D035264:Flowers / Q000502:physiology*; D029595:Orchidaceae / Q000502:physiology*; D011058:Pollen / Q000502:physiology; D054817:Pollination; D013045:Species Specificity
keywords: Neotropical plant communities; Oncidiinae; convergent evolution; deceptive pollination; insect colour vision